frontier

US /frʌnˈtɪr, frɑn-, ˈfrʌnˌtɪr, ˈfrɑn-/

・

UK /'frʌntɪə(r)/

B1
DefinitionVideo subtitles

noun

  • Border crossing between countries
  • Most advanced point of development or research
  • Undeveloped land in which very few people live